1. Field of the Invention
The present invention relates to chip control inserts having diamond segments or other polycrystalline segments adhered thereto to provide excellent cutting, longevity of tool life, and good chip control.
The present invention further relates to an insert having a pocket at its forward end and extending at least partially through the body substrate. A cutting means is interfaced between two wafers of bondable material and bonded into the pocket at one wafer and the other wafer is ground away to form a chip breaker.
2. Description of the Prior Developments
Murray et al., U.S. Pat. No. 4,854,784 discloses a diamond tipped chip control insert which incorporates a polycrystalline diamond or cubic boron nitride material therein as a cutting edge material. The insert substrate includes integral chip control features which eliminate the need for the use of separately attached mechanical chip breakers.
Murray et al differs from the present invention because Murray et al first form a chip breaker from a solid insert, then at one nose portion the insert is provided with a slot which accommodates a polycrystalline diamond material. The diamond is then bonded to the insert in the slot. In the present invention, the chip breaker is formed in the wafer comprised of tungsten carbide/polycrystalline diamond/tungsten carbide after it is bonded to the insert substrate.
Jurgens, U.S. Pat. No. 4,498,549 discloses a cutting member for a rotary drill bit comprised of a substrate to which is bonded a polycrystalline material. The drill does not have any chip breaking features and neither does it utilize the tungsten carbide/polycrystalline diamond/tungsten carbide wafer of the present invention.
Bibbs, Jr. et al., U.S. Pat. No. 4,605,343 discloses a sintered polycrystalline diamond compact having an integral metallic heat sink bonded to and covering at least the outer diamond surface. The metallic heat sink is used to increase compact life when the compact is used for material removal without fluid coolant. The present invention does not require a metallic heat sink to achieve dry cutting and further includes a chip breaker which is absent from Bibbs Jr. et al.
Slutz et al., U.S. Pat. No. 4,899,922 disclose a brazed, thermally stable polycrystalline diamond compact having a network of interconnected empty pores dispersed throughout the compact and bonded to a substrate by a brazing filler metal which may be an alloy having a liquidus above about 700 degrees centigrade. Slutz relates to a manner of bonding the polycrystalline diamond to a substrate. There is no showing in Slutz of using a polycrystalline diamond compact as a metal cutting insert with built in chip control features.